The invention relates to an aircraft and more particularly to a device for monitoring the electronic management of the engines in order to monitor and to re-establish the propulsion capabilities of the aircraft in the case of a total or partial shutdown of the engines.
Each engine of an aircraft is monitored by a control computer which is dedicated to it (EEC, the acronym for “Engine Electronic Control”). Such a computer is connected to a system of sensors installed in the different zones of the engine and of its components in order to measure parameters of the engine and, as a function of the measured parameters, the control computer controls the engine. The control computer moreover uses logic allowing the automatic activation of a protection mode when the measured parameters indicate that the operation of the engine exceeds operational limits predetermined by the manufacturer. The protection mode is, for example, activated in rare situations such as cases of overheating of the engine, leakages of liquids such as oil or kerosene or of damage to structural components of the engine resulting from a shock, for example a bird strike on the blades of the fan of the engine.
The activation of the protection mode comprises either of reducing the thrust authorized by the engine to below its maximum thrust in order to preserve its integrity and to reduce the impact of a failure, or of shutting down the engine. Such a mode makes it possible, in cases of anomalies, to quickly reduce (in less than one second) the demands on the engine in order to reduce the risks of propagation of the anomaly.
It is necessary that the protection mode should only be activated on a single one of the engines, because it is required that only the pilot has the power to operate on all of the engines at the same time. In a known way, in order to comply with this requirement, the control computers are connected to an engine interface device which uses logic for inhibiting the protection modes.
The interface device receives information from the control computer of each engine and, when it knows that a protection mode is activated on an engine, it sends a signal to the control computers of the other engines in order to prevent them from activating the protection mode.
The inhibiting device is effective for preventing the activation of the protection mode on more than one engine.
In the case of a total or temporary failure of the inhibiting device, the computers will each be able to activate the protection mode on the engine associated with it without the interface device being able to prohibit this multiple activation. The requirement mentioned above will therefore no longer be complied with. The pilot will of course be able to manually deactivate the protection modes of the engines but this action will take up some of his time and will divert him from his piloting tasks.
There is therefore a need for an additional device making it possible to prevent several engines from being automatically put into protection mode.